Understanding HTTP Methods & Statuses
Explore the standard HTTP methods (GET, POST, PUT, DELETE) and common HTTP status codes for REST APIs.
Understanding HTTP Methods & Statuses is a free Spring Boot 4 Microservices & REST APIs lesson on CoddyKit — lesson 3 of 3. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Spring Boot 4 Microservices & REST APIs learning path, one of 3 lessons in the course, and your progress syncs across the web and the CoddyKit app.
HTTP Methods: The Verbs of REST
HTTP methods are the verbs of REST — they tell the server the action you want on a resource: get, create, update, or delete data.
GET: Retrieving Resources
GET retrieves data. It’s safe and idempotent — repeat it and you get the same result — and it should never modify anything.
public class HttpGetDemo {
public static void main(String[] args) {
String resourcePath = "/api/products/123";
System.out.println("Simulating GET request for: " + resourcePath);
System.out.println("Expected: Server sends product details.");
}
}POST: Creating New Resources
POST sends data to create a new resource. It’s neither safe nor idempotent: each successful POST typically creates another resource.
public class HttpPostDemo {
public static void main(String[] args) {
String newProductData = "{\"name\":\"Laptop\", \"price\":1200}";
System.out.println("Simulating POST request to create resource with data: " + newProductData);
System.out.println("Expected: Server creates new product and returns its ID.");
}
}PUT: Updating Existing Resources
PUT updates an existing resource (or creates it at that URI). It’s idempotent and usually replaces the entire resource with your data.
public class HttpPutDemo {
public static void main(String[] args) {
String resourceId = "456";
String updatedProductData = "{\"name\":\"Gaming Laptop\", \"price\":1500}";
System.out.println("Simulating PUT request to update resource " + resourceId + " with data: " + updatedProductData);
System.out.println("Expected: Server fully updates product " + resourceId + ".");
}
}DELETE: Removing Resources
DELETE removes a resource. It’s idempotent — delete once and it’s gone; repeat calls may return 404, but the resource stays deleted.
public class HttpDeleteDemo {
public static void main(String[] args) {
String resourceId = "789";
System.out.println("Simulating DELETE request for resource: " + resourceId);
System.out.println("Expected: Server removes product " + resourceId + ".");
}
}HTTP Status Codes: Server's Response
The server replies with an HTTP status code, grouped by class: 1xx info, 2xx success, 3xx redirect, 4xx client error, 5xx server error.
Common 2xx Success Codes
2xx means success: 200 OK (standard), 201 Created (often after POST), and 204 No Content (often after DELETE).
Common 4xx Client Error Codes
4xx means the client erred: 400 Bad Request, 401 Unauthorized, 403 Forbidden, and the famous 404 Not Found.
Common 5xx Server Error Codes
5xx means the server failed: 500 Internal Server Error (generic) and 503 Service Unavailable (overload or maintenance).
Quick Check: Methods & Statuses
Which of the following statements about HTTP methods and status codes are correct?
Recap: Methods & Statuses
You’ve got the REST essentials: methods GET, POST, PUT, DELETE, and status codes grouped 1xx–5xx — the building blocks of any RESTful service.
Frequently asked questions
Is the “Understanding HTTP Methods & Statuses” lesson free?
Yes — the full text of “Understanding HTTP Methods & Statuses” is free to read here on the web, and the Spring Boot 4 Microservices & REST APIs course includes 3 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Spring Boot 4 Microservices & REST APIs course, upgrade to CoddyKit PRO.
What will I learn in “Understanding HTTP Methods & Statuses”?
Explore the standard HTTP methods (GET, POST, PUT, DELETE) and common HTTP status codes for REST APIs. You practise Spring Boot 4 Microservices & REST APIs with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.
Do I need any experience to start Spring Boot 4 Microservices & REST APIs?
No prior experience is required. Spring Boot 4 Microservices & REST APIs on CoddyKit is structured for beginners through advanced learners; this is — lesson 3 of 3, so you can start here or from the beginning and move at your own pace.
How long does the “Understanding HTTP Methods & Statuses” lesson take?
Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.
Can I write and run code in this Spring Boot 4 Microservices & REST APIs lesson?
Yes. Every Spring Boot 4 Microservices & REST APIs lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.
All lessons in this course
- Setting Up Your Spring Boot Project
- Building Your First REST Endpoint
- Understanding HTTP Methods & Statuses